docs: def load_sparql(self,
                      sparql_endpoint,
                      verbose=False,
                      hide_base_schemas=True,
                      hide_implicit_types=True,
                      hide_implicit_preds=True, credentials=None):
          """
          Set up a SPARQLStore backend as a virtual ontospy graph
  
          Note: we're using a 'SPARQLUpdateStore' backend instead of 'SPARQLStore' cause otherwise authentication fails (https://github.com/RDFLib/rdflib/issues/755)
  
          @TODO this error seems to be fixed in upcoming rdflib versions
          https://github.com/RDFLib/rdflib/pull/744
  
          """
          try:
              # graph = rdflib.Graph('SPARQLStore')
              # graph = rdflib.ConjunctiveGraph('SPARQLStore')
              graph = rdflib.ConjunctiveGraph('SPARQLUpdateStore')
  
              if credentials and type(credentials) == tuple:
                  # https://github.com/RDFLib/rdflib/issues/343
                  graph.store.setCredentials(credentials[0], credentials[1])
                  # graph.store.setHTTPAuth('BASIC') # graph.store.setHTTPAuth('DIGEST')
  
              graph.open(sparql_endpoint)
              self.rdflib_graph = graph
              self.sparql_endpoint = sparql_endpoint
              self.sources = [sparql_endpoint]
              self.sparqlHelper = SparqlHelper(self.rdflib_graph, self.sparql_endpoint)
              self.namespaces = sorted(self.rdflib_graph.namespaces())
          except:
              printDebug("Error trying to connect to Endpoint.")
              raise